Preheat oven to 400°. Spray a 13×9-inch baking dish with cooking spray.
In a large saucepan, cook bacon over medium heat until crisp and golden, 5 to 7 minutes. Remove bacon with a slotted spoon, reserving drippings in pan.
In same pan, add butter to drippings and melt over medium heat. Whisk in flour and cook, stirring frequently, for 2 minutes. Gradually whisk in milk until well combined. Cook, stirring occasionally, until thickened, about 5 minutes. Stir in salt, pepper, and ¾ cup Parmesan, stirring until cheese is melted and well combined. Stir in broccoli and cauliflower; remove from heat. Stir in pasta, mozzarella, and lemon zest. Transfer mixture to prepared baking dish.
Cover with foil and bake for 20 minutes. Uncover and sprinkle with remaining ¼ cup Parmesan and bacon. Bake until golden brown and bubbly, about 6 minutes. Let stand for 10 minutes before serving. Garnish with Parmesan and lemon zest, if desired.
Recipe by Taste of the South at https://tasteofthesouthmagazine.com/cheesy-veggie-tortellini/